SCH4C           Lab #10 - Preparation of Nylon 6,6 - a Polymeric Amide

Introduction:  Nylon, a polymer familiar  to everyone because of its wide use in fabrics, is a condensation polymer made by the removal of water molecules from adipic acid,    HOOC-CH2-CH2-CH2-CH2-COOH
and 1,6-diaminohexane:    H2N-CH2-CH2-CH2-CH2-CH2-CH2-NH2

to form the polymer: 

In this experiment, we shall use the chloride of adipic acid, adipyl  chloride,

                                 ClOC-CH2-CH2-CH2-CH2-COCl

which combines with 1,6-diamminohexane by the removal of HCl molecules.   The two reactants will be dissolved in immiscible solvents, so that the reaction takes place only at the interface.  In this way, the polymer can be obtained in strands.

Safety:   Both of the liquids are corrosive and toxic.  Avoid breathing the fumes.  The reaction creates hydrochloric acid as a by-product.  Do not touch the strands with your hands. Use protective gloves and goggles.

Procedure:
1.    Make a hook out of a 10 to 15 cm piece of copper wire and have it in readiness to remove the nylon film as it is formed.
2. Obtain 3 mL of 0.5 M 1,6-diaminohexane in 0.5 M sodium hydroxide (NaOH) solution, and place it in a 50 mL beaker.
3. Hold the beaker containing the 1,6-diaminohexane at a slant, and carefully add 3 mL of a 0.25 M solution of adiply chloride in hexane to it. The two solution are not soluble in each other, so a distinct layer should take place.
4. Use the hooked copper wire to withdraw the film that forms at the boundary of the two liquids.  This is a boundary layer.  Continue to withdraw the film as it forms at the boundary layer until the strand breaks.
5. Place the nylon strand on a previously weighed watch glass and wash generously with water.  Finish with an alcohol rinse.
6. Place the watch glass and nylon in the drying oven to finish drying it overnight.
7. Mass the watch glass and nylon and determine the amount of nylon produced from this reaction.

Questions:
1.    Write equations for the reaction involved in each preparation you performed, using structural formula for the monomers and polymers involved.
2. The nylon produced by the E.I. DuPont de Nemours Company, Nylon, 6-10, is made by condensing sebacic acid,

       HOOC-CH2-CH2-CH2-CH2-CH2-CH2-CH2-CH2-COOH

with 1,6 diaminohexane.  Show how these  molecules can condense and form a long-chain polymer.